Dental injection apparatus

ABSTRACT

APPARATUS FOR SLOWLY AND UNIFORMLY INJECTING LIQUID ANESTHESIA AND THE LIKE COMPRISING A SYRINGE HAVING A COMPRESSIBLE CARTRIDGE THEREIN CONTAINING THE ANESTHESIA, AND PISTON AND CYLINDER MEANS FOR EFFECTING COMPRESSION OF THE CARTRIDGE TO CAUSE THE DESIRED DISPENSING OF THE ANESTHESIA SAID APPARATUS COMPRISING A SUPPLY OF A VISCOUS FLUID, SUCH AS HYDRAULIC OIL, WHICH IS FORCED INTO SAID CYLINDER THROUGH A PORT LOCATED ON ONE SIDE OF THE PISTON AND IS FORCED OUT OF THE CYLINDER THROUGH A PORT LOCATED ON THE OPPOSITE SIDE OF THE PISTON, WHEREUPON MOVEMENT OF THE PISTON IS CUSHIONED BY THE VISCOUS FLUID.

Sept. 20, 1971 M. HODOSH DENTAL INJECTION APPARATUS Filed Dec. 15, 1969INVENTOR HODOSH BY T (9 ATTORNEYS United States Patent 3,605,745 DENTALINJECTION APPARATUS Milton Hodosh, 72 Overhill Road, Providence, RI.02906 Filed Dec. 15, 1969, Ser. No. 884,962 Int. Cl. A61m 5/20 US. Cl.128-218A 5 Claims ABSTRACT OF THE DISCLOSURE Apparatus for slowly anduniformly injecting liquid anesthesia and the like comprising a syringehaving a compressible cartridge therein containing the anesthesia, andpiston and cylinder means for effecting compression of the cartridge tocause the desired dispensing of the anesthesia, said apparatuscomprising a supply of a viscous fluid, such as hydraulic oil, which isforced into said cylinder through a port located on one side of thepiston and is forced out of the cylinder through a port located on theopposite side of the piston, whereupon movement of the piston iscushioned by the viscous fluid.

BACKGROUND OF THE INVENTION During certain surgical and dentalprocedures, and particularly the latter, it is common practice toadminister an anesthetic, such as novocaine, in order to temporarilydeaden sensitive nerves so that the patient will not be compelled toendure undue pain. However, the administration of the anesthetic, in andof itself, is frequently unpleasant and somewhat painful to the patient,and it has been found that the primary cause of the pain and discomfortattendant to the administration of a liquid anesthetic, such asnovocaine, is the fact that conventional injection apparatus administersthe anesthetic too quickly and without suflicient uniformity. It hasbeen found that if the anesthetic is administered slowly and uniformly,almost on a drop-by-drop basis, no pain or discomfort results.

It is not possible, however, to administer the anesthetic slowly enoughand with sufficient uniformity where a hand syringe is used, or whereverpresently known injection apparatus is utilized. It is therefore aprimary object of this invention to provide apparatus that willadminister a liquid anesthetic with extreme slowness and uniformity andwherein the dispensing of the anesthetic is in no way dependent upon themanual dexterity of the person administering same.

SUMMARY OF THE INVENTION As previously stated, the basic concept of thisinvention is the provision of apparatus that will slowly and smoothlyadminister an anesthetic. The apparatus generally comprises a syringehaving therein a collapsable cartridge which houses the anesthetic thatis to be dispensed or injected. A conventional hyperdermic needle is incommunication with the cartridge and extends outwardly from the syringeso that as the cartridge is compressed, the anesthetic will be dispensedthrough the needle.

In order to effect extremely slow and uniform compression of thecartridge, the syringe embodies a cylinder which contains a relativelyviscous fluid, such as hydraulic oil or the like. A reciprocal piston islocated in the cylinder and has means engaging the cartridge to effectcol lapsing thereof in response to movement of the piston. A viscousfluid is introduced to the cylinder on one side of the piston and issimultaneously exhausted from the cylinder on the opposite side of thepiston, the piston will be caused to move, all in a well-known manner,but the fact ice that the piston is moving in a highly viscous fluidpermits the desired slow and uniform movement of the piston to takeplace. The apparatus further comprises a pair of cylinders havingoppositely acting pistons which function to force fluid into the syringecylinder on one side of the piston and at the same time permitexhausting of the fluid from the opposite side thereof. Movement ofthese oppositely acting pistons is achieved by a secondary fluid thathas relatively little or no viscosity, such as air, for example. Thus,the apparatus is basically actuated by compressed air, but thecompressed air, in turn, forces a viscous medium, such as a hydraulicoil or the like, into the syringe cylinder to achieve extremely slow anduniform movement of the syringe piston.

Other objects, features and advantages of the invention shall becomeapparent as the description thereof proceeds when considered inconnection with the accompanying illustrative drawings.

DESCRIPTION OF THE DRAWINGS In the drawings which illustrate the bestmode presently contemplated for carrying out the present invention:

FIG. 1 is a schematic flow diagram showing my apparatus in thenon-operative position thereof;

FIG. 2 is a schematic flow diagram showing the apparatus in operativeposition.

DESCRIPTION OF THE INVENTION Referring to the drawings, there is showngenerally at 10 our injection device comprising a syringe 12 having afixed partition 14- therein defining a dispensing chamber 16 and a fluidchamber 18. A compressible cartridge 20 is located in dispensing chamber16 and has a conventional hyperdermic needle 22 interengaged therewith.The syringe 12 has an opening 24 through which needle 22 passes, itbeing understood that when the cartridge 20 is compressed, by meanshereinafter to be described, the anesthesia or other material containedwithin the cartridge will be dispensed through the needle. A piston 26having a piston shaft 28 is positioned in the fluid chamber 18. Theshaft 28 passes slidingly and sealingly through an aperture 30 in thepartition 14 and has at its extremity a pusher 32 which engages thecatridge 20 to compress same when piston 26 is moved from the positionillustrated in FIG. 1 to the position illustrated in FIG. 2.

The apparatus 10 further comprises a pair of cylinders, 34, 36 havingoppositely acting pistons 38, 40 respectively, mounted therein forreciprocal movement. A conduit 42 communicates with cylinder 34, as atport 44, at one of its ends and with fluid chamber 18, as at port 46, atits opposite end. Likewise, conduit 48 communicates with cylinder 36 atone of its ends, as at port 50, and with fluid chamber 18 at itsopposite end, as at port 52. It will be noted that port 46 is locatedadjacent one extremity of fluid chamber 18 while port 52 is locatedadjacent the opposite extremity thereof.

It will therefore be seen that the portions of cylinders 34 and 36located to the right of pistons 38 and 40, when viewing FIG. 1, alongwith fluid chamber 18 and interconnecting conduits 42 and 48 constitutea closed system which is filled with a relatively viscous fluid, such ashydraulic oil or the like. When piston 38 is moved from the position ofFIG. 1 to the position of FIG. 2 it will be apparent that the viscousfluid in the system will be forced through conduit 42 through port 46 tofluid chamber 18 on the backside of piston 26 thus causing the piston 26to move to the position illustrated in FIG. 2. As piston 26 commences tomove, its shaft 28 slidingly moves through partition 14 thereupon pusher32 causes the cartridge 20 to compress. This in turn dispenses thecontents of cartridge 20 through needle 22. Dueto the highly viscousnature of the fluid in the system, the movement of piston 26 isextremely uniform and may be regulated so as to move extremely slowly.In etfect, the viscous fluid acts as a cushion in the system whichimparts the desired uniformity and slowness to the movement of piston16. Regulating valves 54 and 56 are located in conduits 42 and 48respectively to afford some degree of control over the rate of flow ofthe fluid in the system and hence the rate at which the anesthesia isdispensed. In addition, a bleed valve 58 is connected to cylinder 36 sothat the system may be bled should any air inadvertently becomeentrapped therein.

Since it is desired to have quickly responsive actuating means for theapparatus 10, the pistons 38 and 40 are actuated by means of airpressure. Thus, any suitable source of compressed air is utilized andthe compressed air is fed to conduit 60 through an air pressureregulator 62, and then to a valve 64 having suitable actuating means(not shown) which permits the compressed air to be selectivelyintroduced to conduit 66 or to condut 68. As will be obvious, when valve64 is actuated to introduce air through conduit 66, the compressed airwill enter cylinder 34 at port 70 to cause piston 38 to start movingagainst the oil pressure in the system until the parts reach theposition illustrated in FIG. 2. When it is desired to retract piston 26,valve 64 is actuated to shut off the air flow through conduit 66 and tosimultaneously force air through conduit '68 into cylinder 36 via port72, thus forcing piston 40 to move from the position of FIG. 2 to thatof FIG. 1.

It will be understood that although my invention has prime applicationin the injection of liquid anesthetic, such as novocaine and the like,it is also of value in other applications where an extremely slow anduniform injection is desired. Thus, my apparatus has also proven to beof value when injecting a sealant into a root canal in the course ofdental root canal work. It will also be understood that although FIG. 2shows cartridge 20' completely compressed, the valve 64 may be operatedso as to compress the cartridge only to a desired degree at which pointthe pistons 38 and 40 may be reversed to commence retraction of piston26.

While there is shown and described herein certain specific structureembodying the invention, it will be manitest to those skilled in the artthat various modifications and rearrangements of the parts may be madewithout departing from the spirit and scope of the underlying inventiveconcept and that the same is not limited to the particular forms hereinshown and described.

What is claimed is:

1. An apparauts for injecting liquid anesthetic and the like comprisinga cylinder having closed end walls and a partition therein defining afluid chamber and a dispensing chamber, a compressibe cartridge havinganesthetic therein located in said dispensing chamber, an injectionneedle in communication with said cartridge and extending outwardlythrough the end Wall of said dispensing chamber whereby When saidcartridge is compressed anesthetic is dispensed through said needle, apiston in said fluid chamber having a shaft extending through an openingin said partition and engaging said cartridge to compress sameresponsive to movement of said piston, a supply of viscous fluid in saidapparatus and filling said fluid chamber, flow ports provided adjacentopposite ends of said fluid chamber, a pressure means connected throughone of said ports to cause movement of said piston against the fluidlocated in said fluid chamber on an opposite side of the piston and tosimultaneously force the fluid on the opposite side of the piston outthrough the other port and move said piston to compress said cartridge,and means connected with said other port counteracting the flow of saidfluid out through said other port.

2. In the apparatus of claim 1, said pressure means and counteractingmeans comprising a pair of oppositely acting pistons and cylindersconnnected with said flow ports by conduit means.

3. In the apparatus of claim 2, said conduit means connecting one ofsaid cylinders to one of said ports and the other of said cylinders tothe other of said ports, and flow control means in each of saidconduits.

4. In the apparatus of claim 2, said oppositely acting pistons beingactuated by a low viscosity fluid.

5. In the apparatus of claim 4, said low viscosity fluid being air andsaid viscous fluid being hydraulic oil.

References Cited UNITED STATES PATENTS 2,888,924 6/1959 Dunmire 128-218D2,950,717 8/ 1960 Bouet 128-218D 3,424,154 1/1969 Kinsley 12 8-218RXHUGH R. CHAMBLEE, Primary Examiner U.S. Cl. X.R.

